Concentrations and Risks - Additional information (Detail) (USD $)	3 Months Ended		9 Months Ended				9 Months Ended
	Sep. 30, 2013 Supplier Concentration Risk Cost of Goods, Total Gold	Sep. 30, 2012 Supplier Concentration Risk Cost of Goods, Total Gold	Sep. 30, 2013 Supplier Concentration Risk Cost of Goods, Total Gold	Sep. 30, 2012 Supplier Concentration Risk Cost of Goods, Total Gold	Sep. 30, 2013 China income tax	Dec. 31, 2012 China income tax	Sep. 30, 2013 China income tax Geographic Concentration Risk Assets, Total	Sep. 30, 2012 China income tax Geographic Concentration Risk Assets, Total	Sep. 30, 2013 China income tax Geographic Concentration Risk Sales	Sep. 30, 2012 China income tax Geographic Concentration Risk Sales	Sep. 30, 2013 British Virgin Islands	Dec. 31, 2012 British Virgin Islands	Sep. 30, 2013 United States	Dec. 31, 2012 United States
Concentration Risk [Line Items]
Cash balance excess of FDIC insurance limits					$ 15,707,244	$ 2,515,264					$ 7,605,476	$ 18,457
Cash balance with in United States													$ 4,312	$ 10,393
Concentration of risk percentage	100.00%	100.00%	100.00%	100.00%			100.00%	100.00%	100.00%	100.00%